A home DNS server, SMS gateway, Email server, and lots more for you web developers out there

If you wanted more space than your 32GB SD card can provide, you can hook up an external drive to most phones via USB and use that as your main data storage. The app is definitely geared more toward developers than the average user, but it can be handy if all you want to do is share a few files or run a proxy server at home without keeping your computer on 24/7. An old Android phone is small, low powered, and perfect for hiding in the closet. For more ideas, check out Servers Ultimate's Google Play entry below, or check out this thread on the XDA Developers forums.